/**
 * Created by Administrator on 2016/3/9 0009.
 */
(function (window) {

    var _common= {};
    _common.getScrollTop=getScrollTop;
    _common.getScrollHeight=getScrollHeight;
    _common.getWindowHeight=getWindowHeight;
    //滚动条在Y轴上的滚动距离
    function getScrollTop() {
        var scrollTop = 0, bodyScrollTop = 0, documentScrollTop = 0;
        if (document.body) {
            bodyScrollTop = document.body.scrollTop;
        }
        if (document.documentElement) {
            documentScrollTop = document.documentElement.scrollTop;
        }
        scrollTop = (bodyScrollTop - documentScrollTop > 0) ? bodyScrollTop : documentScrollTop;
        return scrollTop;
    }

    //文档的总高度
    function getScrollHeight() {
        var scrollHeight = 0, bodyScrollHeight = 0, documentScrollHeight = 0;
        if (document.body) {
            bodyScrollHeight = document.body.scrollHeight;
        }
        if (document.documentElement) {
            documentScrollHeight = document.documentElement.scrollHeight;
        }
        scrollHeight = (bodyScrollHeight - documentScrollHeight > 0) ? bodyScrollHeight : documentScrollHeight;
        return scrollHeight;
    }

    //浏览器视口的高度
    function getWindowHeight() {
        var windowHeight = 0;
        if (document.compatMode == "CSS1Compat") {
            windowHeight = document.documentElement.clientHeight;
        } else {
            windowHeight = document.body.clientHeight;
        }
        return windowHeight;
    }


    window.Common = _common;
})(window)